1. Field of the Invention
This invention relates to a one-way clutch used for torque transmission, back stop or overrunning in an automatic variable speed device to be used for an automobile etc., and more particularly to a lubricating device for leading lubricating oil into the inside of a one-way clutch having clutch members such as sprags or rollers.
2. Related Background Art
In a one-way clutch effective to transmit rotary power in one direction only and free running in another direction, clutch members such as sprags or rollers are disposed between inner and outer rings and both end surfaces of the clutch members are guided by side plates. The clutch members engage with the inner and outer rings when the rotary power is transmitted and slip therebetween during free running.
Such a conventional one-way clutch is shown in FIGS. 27 to 32. FIG. 27 shows a one-way clutch where lubricating oil is supplied to clutch members from the inner ring side, FIG. 28 shows the assembly of the one-way clutch, FIG. 29 shows a longitudinal cross section of FIG. 28, and FIG. 30 shows details of the roller arrangement. FIG. 31 shows a one-way clutch where lubricating oil is supplied to clutch members from the outer ring, and FIG. 32 shows an application of a one-way clutch.
In FIG. 27, a conventional one-way clutch 1, where lubricating oil is supplied from inner ring to clutch members, comprises inner ring 2 and outer ring 3, and rollers 4 are disposed between the inner and outer rings. At the inner peripheral surface of outer ring 3, a cam surface 3a is formed in association with each roller 4 to constitute cam structure 5 together with the roller 4 so that the inner ring 2 can rotate relative to outer ring 3 only in one direction. At one side surface of outer ring 3, a step 3b is formed, to which a first side plate 6 fits to effect centering of the first side plate 6. The first side plate 6 covers first end surfaces of rollers 4 and parts of the first side plate 6 are folded to form folded pieces 6a, which penetrate between inner ring 2 and outer ring 3. The front end 6b of each piece 6a projects from the other side of the outer ring. At the other side surface of outer ring 3 a second side plate 7 is provided which covers the other end surfaces of rollers 4. The second side plate 7 has small holes 7a through which folded pieces 6a of the first side plate 6 project, and the front end 6b of each piece 6a is caulked at the outer surface of the second side plate 7 so as to effect centering of the second side plate 7 and to fix both side plates 6 and 7 to outer ring 3. Inner ring 2 has a groove 2a at its inner peripheral surface and lubricating oil filled in groove 2a is supplied to rollers 4 through a lubricating oil hole 2b by centrifugal force.
As shown in FIGS. 28 and 30, centering blocks (pad bearings) 8 are provided between outer ring 3 and inner ring 2. Each centering block 8 comprises a slide part 8a, which slidingly contacts inner ring 2, folded parts 8b engaging with a recess 3c formed at the inner peripheral surface of outer ring 3 and supported by folded pieces 6a, and supporting parts 8c connecting slide part 8a and folding parts 8b. Folding parts 8b of centering block 8 are supported by folded pieces 6a so as to be fixed to recess 3c of outer ring 3.
FIG. 31 shows a conventional one-way clutch 9 where lubricating oil is supplied to the clutch members from outer ring side, with parts corresponding to those in one-way clutch 1 being assigned the same reference numbers. The difference from the one-way clutch where lubricating oil is supplied from inner ring is that instead of the hole 2b and the groove 2a of inner ring 2, a lubricating hole 3c is provided in outer ring 3, and the lubricating oil is supplied through the hole 3c to rollers 4.
The application of one-way clutch 1 is shown in FIG. 32, in which inner ring 2 is welded to a plate 100. In one-way clutches 1, 9, since rollers 4 slide during free running, heating and friction become large unless sufficient lubrication is provided.
The use of a lubricating hole 2c or 3c as previously described leads to a number of practical problems. For example, the presence of the hole leads to stress concentration which can cause damage and reduce the service life of the clutch. Peeling off or scratching of the edge of the hole can occur when the clutch is engaged with the hole being subjected to heavy surface pressure by a clutch member. Although the clutch structure may be reinforced by increasing the thicknesses of the inner and outer rings, this causes the clutch to become undesirably heavy and bulky. As still another problem, the forming of the aforementioned lubricating hole requires a complex and expensive operation.